We studied the Cladocera in four shallow brackish lakes at El Hondo and Salinas de Santa Pola in Mediterranean Spain fromFebruary 1999 to June 2000, sampling each month. We recorded five species : Daphnia magna, D. pulex, D. longispina,Simocephalus exspinosus and Moina brachiata. D. magna was the most abundant species and the only one present all yearround. Total abundance of Cladocera varied significantly between wetlands and months, and was highest in the largest, deepest,least saline wetlands. For a given wetland and month, abundance increased at points of greater depth or lower salinity. Speciesrichness of Cladocera was highest in those seasons and lakes where salinity was lowest, and in those seasons and lakes wherecladoceran abundance was highest. These wetlands hold a particularly high number of waterbird species, but a very low numberof Cladocera species. Ready dispersal via waterbirds does not appear to promote cladoceran diversity in this system, owingto local conditions such as high salinity. We suggest that the conservation value of wetlands for birds is not a good predictor ofvalue for Cladocera.

The predatory behavior of adult females of Thermocyclops decipiens in relation to two cladoceran prey, Ceriodaphnia cornutaand Diaphanosoma spinulosum, was analyzed by laboratory observations. The number of attacks, captures, and ingestionswere quantified. Probabilities of capture after attack (C/A) and ingestion after capture (I/C) were calculated as indicators of preypost-encounter vulnerability. T. decipiens attacked, captured and ingested both cladoceran species, but vulnerabilities of preywere relatively low. C/A was higher in C. cornuta than in D. spinulosum. Larger individuals of D. spinulosum showed higherC/A and I/C than smaller individuals but no effects of size were observed in C. cornuta. The ability of escape as well as thestrength and shape of carapace, seem to partially explain differences in vulnerability among these species. Our results suggestthat intensity of mechanical perturbations and other size-dependent factors, but not body size alone, could be important in determiningpost-encounter prey vulnerability among individuals of a same species.

This study focuses on the host-parasite relationships between species of non-biting midges (Diptera: Chironomidae) and watermites (Acari: Hydrachnidia) in seven springs in Luxembourg. Emergence traps were operated through the season, and identificationof the catches enabled an overview of species composition, abundance and host-parasite associations in the spring communities.Our results show that the Luxembourg springs have similar chironomid diversity to other springs in Europe, and thatparticular species are more often found in certain spring habitats. Furthermore, we show that prevalence of water mite parasitismis highly variable among the sampled chironomid hosts, and that there are several species which were not parasitized despitebeing numerous in our samples. The reasons for the latter observation are discussed, and most of the cases can be explainedby general unavailability of host or parasite, or life cycle incompatibility.

A new species of small cyclopoids from subterranean waters of India is described in a newly established subgenus,Kiefercyclops n.sg., of the genus Haplocyclops Kiefer, 1952. Genital double-somite with ovipores situated in the posterior half,antennula without the lateral seta on the ultimate segment, and caudal rami with the lateral seta inserted in the proximal half areamong the most important characters of H. (K.) fiersi n.sp., that warrant its position in the genus Haplocyclops. Also, the newspecies differs from the other six congeners by several autapomorphic characters, most of them being reductions in armatureand/or segmentation of the appendages. In particular, the degree of reductions concerning the segmentation of the swimminglegs makes it the most reduced free-living cyclopoid, with both rami of third and fourth legs, as well as the endopod of secondleg being one-segmented in both sexes. A key to species of Haplocyclops is given at the end of this paper.

Wetlands are one of the most altered natural systems due to the creation and development of agricultural landscapes. Some ofagriculture’s impacts are in relation to water quality decreases, due to the use of potentially toxic herbicides or pesticides, andthey are responsible of ecological alterations. This study shows the negative effect that two pesticides generate in a populationof the copepod Arctodiaptomus salinus in an aquatic ecosystem that is surrounded by intensive olive tree cultivation. Adultfemales and egg sacs of that calanoid copepod were exposed to different concentrations of copper sulphate and the pesticidedimethoate, to examine their tolerance response. The adult lethal concentration obtained was lower than the regular dose of pesticideused in olive agriculture. These results also reflect the negative effect over A. salinus secondary production as a consequenceof the increase in females and nauplii mortality and by the hatching rate reduction.

In 1996, a compound gauging weir was built in Villaveta Township (Navarra, North of Spain) in the river Erro (Ebro RiverBasin). Before and after its construction, fish and physical and chemical variables were examined to determine weir’s impact onthe reach. Fish captured by electrofishing were measured (total length), and population density and length distribution of thespecies were estimated. Species diversity (Shannon’s diversity index), dominance (Simpson’s dominance index) and evennesswere also calculated. The results revealed an increase in fish population density, especially in smaller specimens, but a decreasein the larger fishes. Substrate and shelter alterations could explain the observed variations in the fish community. In order toimprove the consolidation of well-developed fish populations, the placement of great boulders and the restoration of the riparianvegetation are suggested.

Ecological requirements of ostracods in two limnocrene springs (Usta and Çetin Bey) were investigated between January 2000and July 2002 in Bolu, Turkey. Ten taxa (Candona neglecta, Darwinula stevensoni, Eucypris virens, Eucypris sp., Heterocyprisincongruens, Herpetocypris sp., Ilyocypris bradyi, Potamocypris sp., Scottia pseudobrowniana, Tonnacypris lutaria) werefound. Canonical correspondence analysis (CCA) showed that species with wide cosmopolitan distribution could tolerate highlevels of changes in environmental variables. CCA explained about 80 % and 77 % of the relationships between species andenvironmental variables in Usta and Çetin Bey springs, respectively. Electrical conductivity and dissolved oxygen were the twomost influential factors on species occurrence in each spring. According to Spearman correlation analysis, there were no significantrelationships between the numbers of species and environmental variables in both springs. When dissolved oxygen showedsignificant negative correlations to electrical conductivity, water and air temperature in Usta spring, such correlation wasonly negatively significant (P <0.05, r = -0.46) between electrical conductivity and dissolved oxygen in Çetin Bey spring.Clustering analysis (UPGMA) of presence/absence data divided species into four main groups. Results may suggest that anthropogenicactivities were responsible for decreasing water quality of these springs and reducing species richness. Although increasingincentives for conservation of natural springs were proposed, Çetin Bey spring and especially Usta spring are now highlydegraded.

Microcystis aeruginosa mainly occurs as single cells in laboratory cultures, but in the colonial morph under natural conditions.This phenomenon suggests that some factors may be responsible for the typical occurrence of colonies in lakes. Todemonstrate this possible effect, lake water with abundant or few zooplankton was filtered through a 0.15 µm membrane filter,and used as test water. Microcystis aeruginosa was cultured in BG-11 medium, with or without test water. The results showedthat filtered lake water with abundant zooplankton could induce colony formation in M. aeruginosa, whereas M. aeruginosapopulations in the control and the treatment of filtered lake water with few zooplankton were still strongly dominated by unicellsand paired cells, and no colony was formed. In the treatment of filtered lake water with abundant zooplankton, some coloniesof several, dozens, and sometimes even hundreds of M. aeruginosa cells were formed. The unicells reduced to 53.4±6.5%and the proportion of cells in colonies increased from 0 to 24.5±4.6% of the populations. The mean number of cells per unit ofM. aeruginosa in the treatment of filtered lake water with abundant zooplankton was promoted significantly compared withthose of the control and the treatment of filtrated lake water with few zooplankton. In addition, no significant difference in growthrate was detected between the control and the treatments, regardless to the filtered lake water (i.e. with abundant zooplanktonor with few zooplankton). Thus, we concluded that colony formation in our experiment was probably not associated withthe nutrition difference but with some dissolved substances probably released from abundant zooplankton in the natural lakewater, which may be one of the environmental factors responsible for the colonial form in M. aeruginosa.

We examined diel patterns in fish distribution, size and relative density in a side-channel of the River Garonne before and aftera late-summer spate as part of a study of the role of floodplain wetlands in fish recruitment. Increases in fish size (SL) at nightwere mostly unaffected by the spate, whereas an increase in fish density at night, not observed prior to the spate, was observedin some species post spate. Microhabitat use was variable at dusk and night before and after the spate, but dawn and daytimemicrohabitat use were less variable after the spate. Water velocity, macrophytes and ligneous debris were the most importantmicrohabitat variables prior to the spate, but were replaced thereafter by substratum composition and bank slope. Changes inmicrohabitat electivities were most apparent in abundant species, with shifts in depth, substratum and water velocity preferencesin 0+ gudgeon Gobio gobio and 0+ chub Leuciscus cephalus. Our results indicate that habitat suitability (or preference) curvesand electivity profiles are influenced by variations in river discharge, emphasizing the importance of using multiple samplings(diel, within-season, between-season) when setting habitat criteria for river management and when assessing the role of floodplainwetlands in fish recruitment.

This paper presents a description of the hitherto unknown larva of Drusus muelleri McLachlan, 1868. Information on the morphologicaland genetic identification of this species is given, and the most important diagnostic features are illustrated. Its systematicposition within genus Drusus is affirmed and some zoogeographical and ecological notes are added.

Perennial Oued Zegzel and temporary Oued Cherraa are parts of the same watercourse. Coinertia analysis showed the cleardistinction between these two parts and the close relationship of the faunal assemblages with the characteristics of the water. Theheadwater course of the Zegzel is covered with dense terrestrial vegetation whose debris were consumed by abundant shreddersdominated by the prosobranch Melanopsis praemorsa. The lower course of the Zegzel has sparse riparian vegetation and muchfine detritus, and collectors such as Ecdyonurus rothschildi, Caenis luctuosa, the Diptera Corynoneurinae and Tanytarsini,occurred. In contrast, dry, flowing-, and standing-water periods succeed each other in the Cherraa and terrestrial vegetation oftengrows in its bed. M. praemorsa was replaced by the air-breathing pulmonate Physa acuta, accompanied by the adults and larvaeof flying insects. However many shredders did not develop on the abundant plant litter. The short length of the submersionperiod was probably responsible for this lack of efficiency in the exploitation of such a non-limiting food resource.

This study describes the diet composition of 42 rainbow trout, Oncorhynchus mykiss (Walbaum, 1792) (90-480 mm TL), capturedin May 1995 in the Urederra River (North of Spain). Rainbow trout of all sizes fed mainly on midge (adults, larvae andpupae), but there were some differences in the feeding habits of small and large fish. We found that as the trout grew larger terrestrialprey became the most important food item. Rainbow trout avoided Leuctridae and showed some preference forEphemeroptera, Diptera larvae and Nemouridae larvae. Native fish predation and exploitation of the same trophic resources inthe Urederra River, could negatively affect native fishes, such as European minnow,Phoxinus phoxinus L., 1758 or brown trout, Salmo trutta L., 1758.

The aim of this work was to evaluate the potential of aquatic macrophytes as biological indicators of the environmental conditionsof rivers in north-eastern Spain. To this end, twenty five river basins were studied to assess the species composition andabundance of macrophytes, and to examine their relation with different geographic, morphometric, mineralization, and trophicstatus parameters. Of the twenty six macrophyte species found, five appeared to be useful as biological indicators of the environmentalconditions of the rivers. L. minor was a good indicator of high mineralization (i.e., conductivity and Cl-) and high trophicstate (especially, N-NO2 -). C. stagnalis was a good indicator of high P-PO4 3- concentrations. P. crispus, P. polygonifolius,and R. penicillatus seemed to be useful indicators of high N-NO3 - concentration. We conclude that, in our study area, aquaticmacrophytes can indeed be used as biological indicators of the environmental conditions of rivers.

The pupa of Calamoceras marsupus Brauer, 1865 (Trichoptera : Calamoceratidae) is described and the main taxonomic characteristicsare illustrated. This pupa is compared with those of six genera of Calamoceratidae. The pupa of Calamoceras marsupusshares some characteristics with Banyallarga, Phylloicus, and Ganonema.

In this revision of the 25 French Protonemura, two new taxa are described : P. zhiltzovae sp. n. and P. ausonia padana ssp. n.Moreover, P. spinulosa (Navás 1921) is restored to the species level. Affinities, etymology, ecology and distribution are commentedon for each species. Identification keys and drawings are given for males and females. Finally, Protonemura distributionswithin the main French mountainous massifs are discussed.

The species diversity of Clitellata (a group of annelid worms) is described for three river systems in different parts of southernSweden. The water of one river (Säveån) discharges into the harbour of Göteborg on the Swedish west coast, that of theother two rivers (Svartån and Kilaån) into the Baltic Sea. A total of 143 species, representing the taxa Enchytraeidae (61),Propappidae (1), Lumbricidae (15), Lumbriculidae (6), Tubificidae (4 Rhyacodrilinae, 33 Naidinae, 13 Tubificinae), andHirudinida (10), are reported. Of these, 24 enchytraeids and six lumbricids were found only in the riparian zone, i.e., in the semiaquatichabitats of the river banks. Six species of Enchytraeidae could not be assigned to any known species and are likely tobe new to science. In addition, the following species are recorded from Sweden for the first time : Achaeta brevivasa, Fridericiabenti, F. healyae, F. lenta, F. sylvatica, Oconnorella tubifera (all Enchytraeidae), Aporrectodea limicola (Lumbricidae),Stylodrilus brachystylus (Lumbriculidae), Dero dorsalis, Nais behningi, Haber speciosus, and Peipsidrilus ?saamicus (allTubificidae). Overall, the species composition is typical of today’s fauna of the once glaciated Northern Europe, but for the familyEnchytraeidae, the biogeographical affinity of Sweden is stronger with Denmark and Germany than with, e.g., the British Islesand the eastern parts of Central Europe.

Three new species of Camelobaetidius Demoulin (Ephemeroptera : Baetidae), C. hamadae sp. n., C. lassance sp. n., and C.maranhensis sp. n., are described based on nymphs from Brazil. Some of the diagnostic characters of the new taxa are : C. hamadaesp. n., two thoracic gills at base of forelegs and claws with 36-37 denticles ; C. lassance sp. n., claws with approximately60 denticles and posterior margin of terga with few, large and elevated spines ; C. maranhensis sp. n., pronotum with medialpair of tubercles and terminal filament shorter than 10th abdominal segment. Camelobaetidius cayumba (Traver & Edmunds),C. matilei Thomas &Perú, and C. tuberosus Lugo-Ortiz &McCafferty, are recorded for the first time from Brazil. A key to thespecies of Camelobaetidius recorded from Brazil based on nymphs is presented.

During 2001 - 2002, we studied periphytic biomass at 5 sites along the Agüera stream (Northern Iberian Peninsula), and comparedthe results to those from two previous researches (1990 - 1991 and 1992 - 1993). Sampling sites showed large differencesin cover, conductivity and nutrient contents, as well as some inter-annual differences, resulting from changes in discharge andin human activities. Most environmental variables showed low seasonality, main variations being produced by floods. Solarradiation changed little during 2001 - 2002, because of the coincidence of a sunny winter followed by a cloudy summer, andseasonal differences in riparian cover resulted in more sunlight reaching the streambed of closed sites during winter, and smalldifferences at the open ones. The growth and abscission of riparian leaves results in a strong light regime at the closed sites, withmore sunlight during winter, but this pattern changes from year to year, depending on the weather. Spatial differences and highestvalues of periphytic biomass were much lower than those measured in 1990 - 91, because of contrasting weather patterns.Variables controlling periphytic biomass in the Agüera change from reach to reach. At open sites flow is the main temporalcontroller, whereas at closed sites the effects of light availability prevail, thus giving more similar seasonal patterns from yearto year. Nutrients seem to play a minor role in temporal variations.

Chemical, chemical-physical and biological procedures were employed to carry out a hydrobiological study of a reservoir inthe central Apennines (Italy), designed for the supply of drinking and irrigation water, and tourist recreation facilities.Potentiometric, volumetric, spectrophotometric, and chromatographic techniques were used for the chemical-physical analyses,while the OECD method was adopted to assess the trophic level. The phosphorus and chlorophyll values evidenced the oligomesotrophiccondition of the reservoir, with a dominance of the oligotrophic level. The analysis of the net-phytoplankton communityshowed the prevalence of the oligotrophic level, with a smaller tendency to the mesotrophic one. The dominant specieswere Dinobryon divergens Imhof and D. sertularia Ehrenb. among the Chrysophyceae, and Ceratium hirundinella (O.F. Müll.)Dujardin and Peridinium cinctum Ehrenb. among the Dinophyceae. However, some potentially dangerous inocula (Planktothrixagardhii (Gom.) Anagnostidis et Komárek and Microcystis aeruginosa (Kütz.) Kützing were present, suggesting that the reservoirshould be kept under accurate observation.